Captivated tube shield



Oct. 13, 1959 H. J. MURPHY 2,908,742 CAPTIVATED TUBE SHIELD Filed July13, 1956 IN VENTOR ATTORNEY the chassis.

United States Patent O CAPTIVATED TUBE SHIELD Howard J. Murphy, NorthWilmington, Mass., assignor to United-Carr Fastener Corporation, Boston,Mass., a corporation of Delaware Application July 13, 1956, Serial No.597,719

3 Claims. (Cl. 174-35) The present invention relates to an improvedelectrical shield construction, and more particularly to an improvedtube shield construction for association with electron discharge tubesor the like in electrical apparatus to avoid undesirable reactionsbetween the various ele ments thereof.

A wide variety of shielding means, generally identified as tube shields,have been employed heretofore in electrical apparatus, such as, forexample, radio sets, to dissipate electro-magnetic and electrostaticfields set up therein by the electron discharge tubes during theoperation of the apparatus. While such prior tube shields adequatelyperform their intended shielding function, such tube shields havepossessed many disadvantages which have been found objectionable.

One of the most common forms of tube shields heretofore employed hasconsisted of a simple can or cylinder which is secured to the chassis indetachable relationship therewith by a friction fit or similar fasteningmeans. When a tube is to be replaced in an apparatus employing theso-called can type tube shield, the tube shield is completely detachedfrom the chassis of the apparatus, after which the tube is thenreplaced. Oftentimes the repairman or technician performing theoperation will fail to replace the tube shield with a correspondingimpairment in the operation of the apparatus. Moreover, the failure toreplace the tube shield invariably results in the tube shield being lefton the chassis, thereby resulting in the likelihood of a shortcircuiting of the electrical apparatus. Another disadvantage with thecan type tube shield is that the continued insertion and withdrawal ofthe tube shield from time to time during the replacement results in aloose connection between the tube shield and the chassis. This Willresult in a vibration of the tube shield, oftentimes not insuring apositive grounding of the shield to the chassis.

Another detachable form of tube shield that has received widespreadusage is the so-called shaped shield. This type consists of twosymmetrically paired parts of sheet metal and shaped to fit closely tothe bulb of the tube. The paired parts are held together by a detachablering, a detachable collar, or various other forms of clamping andconnecting parts. Such shaped tube shields, in addition to the basicdisadvantages attendant to detachable tube shields in general, sufferfurther in that all tubes are not one size. Therefore, several differentsizes must be made and stocked, resulting in an unnecessary inventory.Moreover, the design and multiplicity of parts of the shaped tubeshields have resulted in a relatively high cost for such shields, andthey are awkward to assemble and difiicult to satisfactorily ground tothe chassis.

Some attempts have been made to eliminate these disadvantages attendantto the various forms of detachable tube shields by fixedly securing thetube shields to Such fixed tube shield constructions have consisted oftwo mating or paired parts, each of which are hingedly connected attheir bottom ends to one another or to the chassis. To replace a tube inan electrical apparatus employing such a construction, each of themating parts is pivoted upwardly away from one another, the tube thenreplaced, and the component parts then pivoted inwardly to one anotherto envelop and shield the new tube. A principal disadvantage with thistype of tube shield is that it is extravagant of chassis space and doesnot permit the positioning of the tubes to the manufacturersrequirements. Another disadvantage with this form of shield is thatlatching or connecting means between the mating parts to insure properengagement of the shield parts must be present, thereby increasing thecomplexity and cost of such tube shields. Therefore, the permanentlyafiixed tube shields heretofore developed have met with very littlesuccess since compactness of design and simplicity of construction arenecessities in most electrical apparatus.

.11; is therefore a principal object in the elimination of the foregoingand related disadvantages to provide a new and novel tube shieldconstruction overcoming the disadvantages inherent in previouslyemployed tube shields.

Another object of the present invention is the provision of an improvedtube shield construction which will permit replacement of a tube moreeasily than with prior tube shields.

Yet another object of the present invention is the provision of animproved tube shield construction which will be permanently afiixed tothe chassis, thereby insuring the proper functioning of the tube shieldat all times.

A further object of the present invention is the provision of animproved tube shield construction that requires a minimum amount ofchassis space.

A still further object of the present invention is the provision of animproved tube shield construction in which the component parts will bein proper engagement with one another at all times.

Another object of the present invention is the provision of an improvedtube shield construction that will remain in tight engagement and inproper grounded relationship with the chassis at all times.

A still further object of the present invention is the provision of animproved tube shield construction that is of extreme simplicity indesign and operation, and inexpensive to manufacture.

Other and additional objects will become apparent from the ensuingdescription taken in conjunction with the accompanying drawings.

Broadly stated, in the attainment of the foregoing objects, the tubeshield construction of the present invention comprises inner and outersleeve means, one of said sleeve means having connecting meanspositioned at one end thereof for securing same to a chassis in fixedrelationship thereto, the other of said sleeve means being rotatablerelative to the fixed sleeve means, the top portion of the outer andinner sleeve means each being provided with diametrically opposedlongitudinal slots therein, and stop means preferably being provided tolimit the rotation of said rotatable sleeve means. The rotatable sleevemeans is advantageously arranged exteriorly of the fixed sleeve means,and the assembly is preferably arranged to retain the rotatable sleevemeans against removal.

To the accomplishment of the foregoing and related ends, the presentinvention then consists of the means hereinafter fully described andparticularly pointed out in the claims, the annexed drawing and thefollowing description setting forth in detail certain means in thecarrying out of the invention, such disclosed means illustrating,however, but one of various Ways in which the principle of the inventionmay be employed.

The present invention is illustrated by' way of example in theaccompanying drawings, in which:

Figure 1 is a perspective view of outer sleeve means forming a componentpart of a tube shield construction made in accordance with the presentinvention.

Figure 2'is a' perspective view of the inner sleeve means to beassociated with said outer sleeve means to form a tube shieldconstruction made in accordance with the present invention.

Figure 3 is a perspective view of a tube shield construction made inaccordance with the present invention with the outer shield in openedposition to permit the insertion or withdrawal of a tube.

Figure 4 is a perspective view of a tube shield construction made inaccordance with the present invention illustrating the outer sleevemeans in closed position to provide the desired shielding.

Reference is now to be had to the drawings wherein an illustrativeembodiment of a tube shield construction made in accordance with thepresent invention and gen erally designated by reference numeral isshown. The tube shield construction 10 as shown comprises an outertubular sleeve member A enveloping an inner tubular sleeve member B, oneof which is to be fixedly secured to a support to permit relativerotation of the sleeve members A and B with respect to one another.

The outer tubular sleeve member A, as shown in Fig. 1, is of a heightand diameter sufficient to envelop the desired electron discharge tube,and comprises a lower body portion 11 and a pair of opposed arm portions12 and 13 extending upwardly therefrom in longitudinal alignmenttherewith. The opposed arm portions 12 and '13 result in the formationof opposed slots extending upwardly from the top free edges 14 and 15 ofthe lower body portion 11 and being of a width and longitudinal lengthsuflicient to permit the engagement of the thumb and finger of atechnician therebetween. Each of the arm portions 12 and 13 are providedwith outwardly extending flange portions 16 and 17 extendinglongitudinally along each vertical side edge thereof to enable thesleeve member A to be rotated, and also to limit such rotation in amanner to be more fully described hereinafter.

The outer sleeve member A may be made from any suitable metal that iscapable of possessing some degree of flexibility but yet has sufficientstrength to resist bending or distortion. The outer sleeve member A maybe made in any desired manner, and preferably is formed from a flatblank of sheet metal which is rolled to the required diameter with thefree ends of the lower base portion 11 overlapping one anothercircumferentially as along the line 18.

The inner tubular sleeve member B, as shown in Fig. 2, likewise is of aheight and diameter sufficient to envelop the electron discharge tube,although the diameter of the inner sleeve member B should be justslightly less than that of the outer sleeve member A, so as to permitthe outer sleeve member A to be in engagement therewith and yet bereadily rotatable therearound without creating unnecessary distortionalstrains.

The inner sleeve member B comprises a lower base portion 19 having apair of opposed arm portions 20 and 21 extending upwardly therefrom inlongitudinal alignment therewith. The length and the width of the armportions 20 and 21 of the inner sleeve member B are substantiallyidentical with the length and width of the arm portions 12 and 13 of theouter sleeve member A. Stop means in the form of a triangular earportion 22 extends outwardly from the side edge of the arm portion 20immediately adjacent the point of jointure with the lower base portion19. The function of the ear portion 22 is to insure the positiveretention of the outer sleeve member A on the inner sleeve member B, andto also limit the rotational movement of the outer sleeve by member Aengaging the flange portions carried by the arms struction can beemployed equally as well.

12 and 13 in a manner to be more fully described hereinafter.

The inner sleeve member B is provided with lug portions 23 at the bottomfree end of the lower base portion 19 on opposite sides thereof topermit the engagement and securing of the inner sleeve member B to achassis plate C by means of screws or bolts 24. It is to be clearlyunderstood that these securing means are illustrative in character only,since there are a wide variety of other available attaching means bywhich the inner sleeve member B may be secured to the chassis C.

The inner sleeve member B may be made from the same material and in thesame manner as the outer sleeve member A. A preferred method, ashereinbefore indicated, is to roll the sleeve member B from a flat blankto the desired diameter, with the free end of the lower base portion 19overlapping one another along line 25.

To employ the tube shield construction 10, the inner sleeve member B issecured to the chassis C over the tube socket opening by means of thescrew or bolt 25' passing through the lugs 24. To insert the outersleeve member A over'the inner sleeve member B, the lower base portion11 of the outer sleeve member A is placed over the free ends of theopposed arm portions 20 and 21 of the inner sleeve member B, and inlongitudinal alignment therewith. The outer sleeve member A is then sliddownwardly with the bottom free end of the lower base portion 11striking the ear 20. A continual pressure downwardly at this point willcause the lower base portion 11 to flex circumferentially, permittingthe lower base portion 11 to be slid thereover until the top edge 14 ofthe lower base .portion 11 which defines the bottom edge of the slotwill sleeve member A from the inner sleeve member B without actuallydeforming same.

To insert an electron discharge tube into the shield construction it theouter sleeve member A is rotated until the opposed arm portions 12 and13 are in mating relationship with the opposed arm portions 19 and 20 ofthe inner sleeve member B, giving accessibilty thereto by means of theopposed longitudinal slots. The tube D is then inserted in the socket bygrasping the opposed side edges of the tube with the thumb and fingerand pushing same downwardly into its socket, with the thumb and fingerriding downwardly in the opposed slots. It Will be noted when the tubeshield construction is in open position that the ear portion 20 engagesthe flange 16 of the arm portion 12 of the outer sleeve member Avtoprevent its rotation to a point beyond that needed to bring therespective arm portions of the sleeve members A and B in registry ormating relationship with one another.

To provide the necessary shielding of the electron discharge tube, theouter sleeve member A is grasped along the flange portions 14 and 15 androtated in a direction opposite to that employed for opening the tubeshield construction 10. The outer sleeve member A is rotated until theflange portion 17 of the arm portion 13 carried by the outer sleevemember A strikes the protruding ear portion '21). At this point theopposed arm portions 12 and 13 of the outer sleeve member A willcompletely close the slots of the inner sleeve member B forming acomplete tubular shield for the electron discharge tube.

It should be noted that in the illustrative form of the inventionhereinbefore described, the inner sleeve member has been shown in fixedposition with the outer sleeve member being rotatable relative thereto.However, it should be clearly understood that this is in no way to beconstrued as a limitation, since the reverse of this con- In thisreversed form, the outer sleeve member will be in fixed relation and theinner sleeve member movable relative thereto.

While there have been described herein what are at present consideredpreferred embodiments of the invention, it will be obvious to thoseskilled in the art that modifications and changes may be made thereinwithout departing from the essence of the invention. It is therefore tobe understood that the exemplary embodiments are illustrative and notrestrictive of the invention, the scope of which is defined in theappended claims, and that all modifications that come within the meaningand range of equivalency of the claims are intended to be includedtherein.

I claim:

1. A tube shield construction for shielding an electron discharge tubeassociated with a support comprising inner sleeve means, connectingmeans at one end of said inner sleeve means for securing same to asupport in fixed relation thereto, the opposite end of said sleeve meansbeing provided with a pair of diametrically opposed, free arm portionsextending upwardly therefrom in generally longitudinal alignmenttherewith forming a pair of diametrically opposed longitudinallyextending slots therebetween of a width sufiicient to enable the fingersof an operator to extend therethrough to grasp a tube positionedtherein, rotatable outer sleeve means enveloping said inner sleevemeans, the top portion of said outer sleeve means being provided with apair of diametrically opposed, free arm portions extending upwardlytherefrom in generally longitudinal alignment therewith forming a pairof diametrically opposed, longitudinally extending slots therebetween ofa width sufficient to enable the fingers of an operator to extendtherethrough to grasp a tube positioned therein, said inner and outersleeve means being of substantially the same height and each having asubstantially uniform diameter throughout their longitudinal lengths,said free arm portions of said inner and outer sleeve means beingcomplementary with one another whereby upon rotation of the outer sleevemeans the formed diametrically opposed slots in the inner sleeve meanswill be overlapped by the arm portions of said outer sleeve means toshield a tube positioned therein, stop means on one of said sleeve meansto limit the rotation of said outer sleeve means, and retaining means toprevent the separation of said inner and outer sleeve means from oneanother.

2. A tube shield construction in accordance with claim 1 wherein thestopmeans is secured along a longitudinal edge of one of said armportions of said fixed sleeve means.

3. A tube shield construction in accordance with claim 1 wherein thestop means holds the rotatable sleeve means in enveloping relation withsaid fixed sleeve means to prevent its longitudinal Withdrawaltherefrom.

References Cited in the file of this patent UNITED STATES PATENTS1,290,440 Wells Jan. 7, 1919 1,928,408 Clavier Sept. 26, 1933 1,980,183Brosilow et al Nov. 13, 1934 2,019,939 Suller Nov. 5, 1935 2,080,913Hafecost et a1. May 18, 1935

